While it is widely agreed that current enterprise resource planning (ERP) systems cannot evolve much further, it is the question how future enterprise systems will look like. To approach an answer to this question, this report provides at first an analysis of essential high level requirements and their implications. Against this background, a conception of future enterprise systems referred to as self-referential enterprise systems (SRES) is presented. It is characterized by an elaborate conceptual foundation, which is based on multi-perspective enterprise models. These models enable enterprise software to not only refer to their conceptual foundation, but also to the concepts that characterize the context they are embedded in. In order to promote cross-organizational integration and high-level reuse, it is suggested to develop reference models, which provide design blueprints for an entire range of organizations. While the development of reference models and the realization of corresponding SRES is a very attractive research vision, it overextends the resources of single research institutions by far. It also requires involving prospective users. To cope with these challenges, the paper suggests a conception of collaborative development of open reference models. It concludes with the description of the recently launched Open Model initiative that is aimed at promoting the joint development of large conceptual models which could serve as a foundation of future SRES.